Abstract :
The effect of the anti-moulting agent diflubenzuron were studied against the nymphal instars Berseem Grasshopper Euprepocnemis Plorans Plorans (Charp) .The tested rates of 40 / 20 / 10 gm. a.i /fed. were sprayed on alfa alfa Medicage sativa. Groups of 4th instar nymphs were continuously fed on the treated alfa alfa to the next moult to 5th instar. This treatment induced low percentages of failure in ecdysis to the 5th instar. The high percentages of failure in ecdysis and mortality were obtained within the 5th instar especially during metamorphosis to the adult stage . The prolonged duration of the treated 4th instar and the decreasing of the body weight of the resulting 5th nymphs and the corresponding adults, specially in the treatment with the high rate (40 gm.a.i/fed.) suggested that. Diflubenzuron was a rate dependent against grass hopper E. Plorans Plorans, and this compound could be a good preventive control tool against the nymphal instars of this insect pest in their breeding sites.
